Separation of Ethanol–Water Mixtures Using Molecular Sieves and Biobased Adsorbents

Al‐Asheh, Sameer; Banat, Fawzi; Al-Lagtah, Nasir

doi:10.1205/0263876041596779

Cited by 108 publications

(70 citation statements)

References 17 publications

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“…There are a number of adsorbents that can be employed to dry ethanol: zeolite (Jeong et al, 2009;Simo et al, 2009), silica gel, activated alumina, cassava (Boonfung and Rattanaphanee 2010;Liu et al, 2010;Quintero and Cardona 2009), cornmeal (Chang et al, 2006b;Hu and Xie 2001;Vareli et al, 1998), wood chips (Boonfung and Rattanaphanee 2010;Benson and George 2005), potato starch (Hu and Xie 2001), natural corncobs, natural and activated palm stone, oak (Al-Asheh et al, 2004). Among these adsorbents, 3A zeolite and corn grit are currently used in ethanol plants to dry ethanol (Kim et al, 2011;Simo et al, 2009).…”

Section: Adsorbentsmentioning

confidence: 99%

“…Bio-adsorbents that have been extensively studied for ethanol dehydration purposes, include cassava (Boonfung and Rattanaphanee 2010;Liu et al, 2010;Quintero and Cardona 2009), cornmeal (Chang et al, 2006b;Hu and Xie 2001;Vareli et al, 1998), wood chips (Boonfung and Rattanaphanee 2010;Benson and George 2005) natural corncobs, natural and activated palm stone and oak (Al-Asheh et al, 2004). However, other bio-based adsorbent such as canola meal have not been systematically investigated for this purpose.…”

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confidence: 99%

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Ethanol Dehydration in a Pressure Swing Adsorption Process Using Canola Meal

2013

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Canola meal was used as an adsorbent in a pressure swing adsorption (PSA) apparatus for ethanol dehydration. The experiments were conducted at different pressures, temperatures, vapor superficial velocities, vapor concentrations and particle sizes. Adsorption experiments were performed at equilibrium and breakthrough points. The results demonstrated that canola meal can break the azeotropic point 95.6 wt% and produce over 99 wt% ethanol. At elevated temperature, feed water concentration, and vapor superficial velocity, it was found that the mass transfer rate increased. In addition, the mass transfer rate decreases when either the total pressure or the size of the adsorbent particles are increased. Breakthrough curves were simulated and the overall mass transfer resistance was evaluated at all experimental runs. The internal mass transfer resistance was identified as the relevant mass transfer mechanism.For canola meal, the equilibrium water/ethanol uptake was achieved at 100, 105, and 110˚C. The Frenkel-Halsey-Hill (FHH) and Guggenheim-Andrson-de-Boer (GAB) models perfectly simulated the water adsorption isotherms. By applying Dubinin-Polanyi model to the experimental data, canola meal was identified as a large pore (non-porous) material.The heat of adsorption on canola meal with particle size of 0.43-1.18 mm was determined to be -32.11 kJ/mol. The result confirms that the adsorption process is an exothermic phenomenon and is of physical type due to the fact that the value obtained as the heat of adsorption is negative and its magnitude is within the range 20-80 kJ/mol. The equilibrium water uptake on canola meal was similar to that reported for other starchy and cellulosic adsorbents, while the ethanol uptake was higher.Water saturated canola meal was successfully regenerated by passing nitrogen at 110˚C which is lower than that for molecular sieves commonly used in industry for bioethanol dehydration. The canola meal bio-adsorbent was re-used for more than 32 cycles and no significant change in adsorption capacity was observed.iii ACKNOWLEDGEMENTS

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Section: Adsorbentsmentioning

confidence: 99%

mentioning

confidence: 99%

Ethanol Dehydration in a Pressure Swing Adsorption Process Using Canola Meal

2013

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“…The samples with acid-washing pretreatment prior to the  fusion process demonstrated a greater adsorption capacity than the samples without acid-washing pretreatment. Among all synthesized samples, Z-HCl-F550-Na2.25-C20 shows the highest water adsorption capacity; its adsorption performance is comparable to the commercial grade molecular-sieve and reported adsorption values (molecular-sieve type 3A, 4A, 5A and biobased adsorbents) [19]. From the results, more than 99%wt ethanol concentration could be achieved using Z-HCl-F550-Na2.25-C20 via the adsorption process (described in Section 2.4).…”

Section: Performance Of Synthesized Zeolite As Water Sorbentmentioning

confidence: 72%

“…From the results, more than 99%wt ethanol concentration could be achieved using Z-HCl-F550-Na2.25-C20 via the adsorption process (described in Section 2.4). Note that the reported adsorption capacities are in the range of 0.087-0.127 gwater gadsorbent -1 [19] while Z-HCl-F550-Na2.25-C20 had an adsorption capacity of 0.158 gwater gadsorbent -1 . This result clearly indicates the importance of material purity, phase formation and specific surface area on the water adsorption performance, in which the material with high purity, with the presence of Na-faujasite phase and with high specific surface area can gain high water adsorption performance.…”

Section: Performance Of Synthesized Zeolite As Water Sorbentmentioning

confidence: 96%

Synthesis and Testing of Zeolite from Industrial-Waste Coal Fly Ash as Sorbent For Water Adsorption from Ethanol Solution

Panitchakarn¹,

Klamrassamee²,

Laosiripojana³

et al. 2014

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Abstract. In the present work, zeolite was prepared from industrial-waste coal fired ash (CFA) by fusion technique with and without acid-washing pretreatment under various conditions. The synthesized materials were then tested for water adsorption from bioethanol solution with an aim to produce a high purity ethanol (>99.5%) for later utilization in gasohol production manufacturing. From our studies, it was found that the impurities (i.e., Fe2O3, TiO2, MgO, CaO, K2O and SO3) in CFA could be efficiently removed by acid-washing pretreatment. Among three different acids studied (i.e. HCl, HNO3, and H2SO4), HCl exhibited the highest pretreatment performance, while the most suitable pretreatment conditions to enhance high purity raw material (up to 85% purity) were by using 20%HCl with the acid to CFA ratio of 25 mlHCl/gCFA at 80°C for 3 h. After fusion at 550ºC with NaOH/CFA mass ratio of 2.25 and further crystallization at 90ºC for 4 h, the pretreated CFA was converted to zeolite; from which the main phases were sodium aluminum silicate hydrate (1.08Na2O•Al2O3•1.68SiO2•1.8H2O) and faujasite-Na (Na2Al2Si2. 4O8.8•6.7H2O). Regarding water adsorption testing, the synthesized zeolite provided comparable adsorption performance with the commercial grade molecular sieve. Under three adsorption cycles testing at 85ºC, high ethanol purity (99.8%) could be achieved without deactivation being observed.

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“…50% to 80% of the total energy is consumed in the ethanol recovery step of a typical manufacturing process, and most of this energy is consumed in distilling the ethanol to concentrations of more than 85%. Many ethanol recovery methods have been proposed to replace the distillation method, such as membrane separation 3) , adsorption 4) and supercritical fluid extraction 5) . The newly developed and conventional methods were recently reviewed comprehensively 6) .…”

Section: Introductionmentioning

confidence: 99%

Extraction Equilibrium of Ethanol for Bioethanol Production — Solvent Selection and Liquid-liquid Equilibrium Measurement —

Habaki

Tabata²,

Kawasaki

et al. 2010

J. Jpn. Petrol. Inst.

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Ethanol distributions between selected organic and aqueous phases were measured for recovery and concentration of bioethanol from fermented solution. The strategy of solvent selection was based on the background of biofuel production, and m-xylene was selected as the primary solvent and capric acid, 1-hexanol and 2-ethyl hexanol secondary solvents were utilized to enhance the ethanol solubility. The extraction performance was evaluated through the liquid-liquid equilibrium. m-Xylene showed low distribution coefficient of ethanol and high separation selectivity of ethanol relative to water. All secondary solvents increased the distribution coefficient. The separation selectivity was greatly reduced by capric acid, but was similar for 1-hexanol and 2-ethyl hexanol. The two phase region was smaller for 1-hexanol than for 2-ethyl hexanol, chosen as the best secondary solvent. Examination of the effects of 2-ethyl hexanol concentration in the solvent found that a small amount of 2-ethyl hexanol could enhance the distribution coefficient and maintain the separation selectivity constant. The measured liquid-liquid equilibria were estimated with the ordinary and modified UNIFAC methods. Both methods could predict the liquid-liquid equilibrium behaviors of the measured systems, but the modified UNIFAC method could show a better correlation. However, the water concentrations in the organic phases were estimated to be larger than the measured values if the measured concentrations were very low.

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Separation of Ethanol–Water Mixtures Using Molecular Sieves and Biobased Adsorbents

Cited by 108 publications

References 17 publications

Ethanol Dehydration in a Pressure Swing Adsorption Process Using Canola Meal

Ethanol Dehydration in a Pressure Swing Adsorption Process Using Canola Meal

Synthesis and Testing of Zeolite from Industrial-Waste Coal Fly Ash as Sorbent For Water Adsorption from Ethanol Solution

Extraction Equilibrium of Ethanol for Bioethanol Production — Solvent Selection and Liquid-liquid Equilibrium Measurement —

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